CVE-2026-42599

MEDIUMNVD 6.16.1—
EchelonGraph scoreMEDIUM confidence

This medium-severity CVE scores 6.1 under NVD CVSS v3. EPSS exploit probability: 0.2%, top 94% of all CVEs by exploit prediction. GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).

Triggered by: NVD CVSS baseline
Sources: epss, nvd
6.1
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS: 0%CVSS: 6.1Exploit: NoneExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

Svelte is a performance oriented web framework. Prior to version 5.55.7, when using spread syntax to render attributes from untrusted data, event handler properties are included in the rendered HTML output. If an application spreads user-controlled or external data as element attributes, an attacker can inject malicious event handlers that execute in victims' browsers. Note that this vulnerability only triggers if the user's browser has JavaScript enabled but Svelte's hydration mechanism does not reach the vulnerable element before the event fires. This issue has been patched in version 5.55.7.

CVSS v3
6.1
EG Score
6.1(medium)
EPSS
6.4%
KEV
Not listed

Published

June 9, 2026

Last Modified

June 11, 2026

Advisory Details (2)

Auto-updated Jun 16, 2026
Patch available. Sources: github, github_release.
github Patch Available

Cross-site scripting via spread attributes in Svelte SSR · Advisory · sveltejs/svelte · GitHub

https://github.com/sveltejs/svelte/security/advisories/GHSA-pr6f-5x2q-rwfp
github_release Patch Available

[email protected]

Patch available: sveltejs/svelte [email protected]

https://github.com/sveltejs/svelte/releases/tag/svelte%405.55.7

Vendor Advisories for CVE-2026-42599(1)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Affected Packages

(1 across 1 ecosystem)
npm(1)
PackageVulnerable rangeFixed inDependents
svelte—5.55.7—

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 11× in last 7d / 58× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

  1. 2026-07-12 05:46 UTCEPSS rescore
  2. 2026-07-11 22:13 UTCEG score recompute
  3. 2026-07-11 08:27 UTCEPSS rescore
  4. 2026-07-10 19:49 UTCEG score recompute
  5. 2026-07-09 19:10 UTCEPSS rescore
  6. 2026-07-09 02:29 UTCEG score recompute
  7. 2026-07-08 15:15 UTCEPSS rescore
  8. 2026-07-07 23:06 UTCEG score recompute
  9. 2026-07-07 13:46 UTCEPSS rescore
  10. 2026-07-06 16:27 UTCEPSS rescore
  11. 2026-07-06 16:27 UTCEPSS rescore
  12. 2026-07-05 15:46 UTCEG score recompute
  13. 2026-07-05 02:30 UTCEPSS rescore
  14. 2026-07-04 13:22 UTCEG score recompute
  15. 2026-07-04 06:31 UTCEPSS rescore
  16. 2026-07-03 03:00 UTCEG score recompute
  17. 2026-07-02 00:36 UTCEG score recompute
  18. 2026-07-01 15:06 UTCEPSS rescore
  19. 2026-06-30 23:22 UTCEPSS rescore
  20. 2026-06-30 22:06 UTCEG score recompute
  21. 2026-06-29 19:41 UTCEG score recompute
  22. 2026-06-29 14:06 UTCEPSS rescore
  23. 2026-06-28 17:18 UTCEG score recompute
  24. 2026-06-28 14:07 UTCEPSS rescore
  25. 2026-06-28 04:56 UTCEPSS rescore
Show 40 more
  1. 2026-06-27 14:55 UTCEG score recompute
  2. 2026-06-27 03:08 UTCEPSS rescore
  3. 2026-06-26 12:32 UTCEG score recompute
  4. 2026-06-25 13:49 UTCEPSS rescore
  5. 2026-06-25 13:49 UTCEPSS rescore
  6. 2026-06-25 03:31 UTCEG score recompute
  7. 2026-06-24 14:05 UTCEPSS rescore
  8. 2026-06-24 01:06 UTCEG score recompute
  9. 2026-06-23 21:33 UTCEPSS rescore
  10. 2026-06-22 22:40 UTCEG score recompute
  11. 2026-06-22 14:25 UTCEPSS rescore
  12. 2026-06-22 14:25 UTCEPSS rescore
  13. 2026-06-21 20:12 UTCEG score recompute
  14. 2026-06-21 14:56 UTCEPSS rescore
  15. 2026-06-21 14:56 UTCEPSS rescore
  16. 2026-06-21 01:59 UTCEPSS rescore
  17. 2026-06-20 17:34 UTCEG score recompute
  18. 2026-06-19 19:25 UTCEPSS rescore
  19. 2026-06-19 15:00 UTCEG score recompute
  20. 2026-06-18 17:52 UTCEPSS rescore
  21. 2026-06-18 17:52 UTCEPSS rescore
  22. 2026-06-18 12:28 UTCEG score recompute
  23. 2026-06-17 17:53 UTCEPSS rescore
  24. 2026-06-17 09:58 UTCEG score recompute
  25. 2026-06-16 17:52 UTCEPSS rescore
  26. 2026-06-16 07:35 UTCEG score recompute
  27. 2026-06-15 17:49 UTCEPSS rescore
  28. 2026-06-15 05:13 UTCEG score recompute
  29. 2026-06-14 02:47 UTCEG score recompute
  30. 2026-06-13 23:00 UTCEPSS rescore
  31. 2026-06-13 00:24 UTCEG score recompute
  32. 2026-06-12 23:12 UTCEPSS rescore
  33. 2026-06-12 23:12 UTCEPSS rescore
  34. 2026-06-11 22:02 UTCEG score recompute▲ 1.00
  35. 2026-06-11 19:56 UTCNVD updateCVSS v3 → 6.1
  36. 2026-06-11 14:00 UTCEPSS rescore
  37. 2026-06-10 22:18 UTCEPSS rescore
  38. 2026-06-10 19:40 UTCEG score recompute
  39. 2026-06-09 17:17 UTCEG score recompute
  40. 2026-06-09 17:17 UTCNVD updatefirst tracked

Related CVEs(same CWE)

Frequently asked(5)

What is CVE-2026-42599?
CVE-2026-42599 is a medium vulnerability published on June 9, 2026. Svelte is a performance oriented web framework. Prior to version 5.55.7, when using spread syntax to render attributes from untrusted data, event handler properties are included in the rendered HTML output. If an application spreads user-controlled or external data as element attributes, an…
When was CVE-2026-42599 disclosed?
CVE-2026-42599 was first published in the National Vulnerability Database on June 9, 2026, with the most recent update on June 11, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-42599 actively exploited?
CVE-2026-42599 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 6.4% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2026-42599?
CVE-2026-42599 has a CVSS v3 base score of 6.1 (NVD).
How do I remediate CVE-2026-42599?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-42599, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

Dependency Blast Radius

See which npm, PyPI, Go, and Maven packages are affected by CVE-2026-42599

Explore →

Is Your Infrastructure Affected by CVE-2026-42599?

EchelonGraph automatically scans your cloud infrastructure and maps CVE exposure using blast radius analysis.

Start Free Scan →Browse All CVEs